212 citations · 848 across the 74 of their papers we have counts for
27 papers · 1 filter
Global Rational Approximations of Functions With Factorially Divergent Asymptotic Series
N. Castillo, O. Costin, R. D. Costin
We construct a new type of convergent, and asymptotic, representations, dyadic expansions. Their convergence is geometric and the region of convergence often extends from infinity…
On the domain of convergence of spherical harmonic expansions
O. Costin, R. D. Costin, C. Ogle +1
Spherical harmonic expansions (SHEs) play an important role in most of the physical sciences, especially in physical geodesy. Despite many decades of investigation, the large order…
A new type of factorial series expansions and applications
O. Costin, R. D. Costin
We construct a new type of convergent asymptotic representations, dyadic factorial expansions. Their convergence is geometric and the region of convergence can include Stokes rays,…
From Taylor series of analytic functions to their global analysis
Ovidiu Costin, Xiaoyue Xia
We analyze the conditions on the Taylor coefficients of an analytic function to admit global analytic continuation, complementing a recent paper of Breuer and Simon on general cond…
A quasi-solution approach to nonlinear problems - the case of Blasius similarity solution
O. Costin, T. Kim, S. Tanveer
Using the simple case of Blasius similarity solution, we illustrate a recently developed general method that reduces a strongly nonlinear problem into a weakly nonlinear analysis.…
Tronquée solutions of the Painlevé equation \P1
O. Costin, R. D. Costin, M. Huang
We analyze the one parameter family of tronquée solutions of the Painlevé equation \P1 in the pole-free sectors together with the region of the first array of poles. We find a conv…